92 CONTRIBUTIONS TO PAL.EONTOLOGY 



Thickness 

 in feel 



Sandstone, raassive, yellowish brown 22.0 



Shale, sand}', bluish gray 6.0 



Sandstone, friable, yellowish, with soft, sandy light-colored shale 1150.0 



Sandstone, friable, massive, concretionary, shaly in places, with some hard brown, 

 slightly calcareous sandstone and a few bands of soft sandy shale; Unios found 



at top 570.0 



Shaie and sandstone, banded 30.0 



Sandstone, massive, yellowish brown, with the following fossils [identified by 

 C. AV. Gilmore] : 



Tooth of Triceratops 



Fragment of the carapace of a soft-shelled turtle, probably belonging to 



the genus Aspiderates 25.0 



Sandstone, shaly, with some shale 25.0 



Sandstone and shale; light colors prevailing 120.0 



Sandstone, massive, yellowish brown, friable 12.0 



Shale, carbonaceous, sandy, and sandstone, soft 20.0 



Total Lance formation 2539.5 



Fox Hills sandstone: 



Sandstones, yellowish brown, soft, interbedded with sandy, light-colored shale 

 [probably in part Lancej 



The lower limit of the Lance formation has been discussed under the Fox Hills 

 sandstone. The upper limit, following its original definition, has been conveniently 

 drawn at the top of the dinosaur-bearing beds. This horizon coincides with a 

 marked change, without a recognized erosional or structural unconformity, from the 

 characteristic dull-gray shales and shaly sandstones of the typical Lance formation 

 to a sequence of more persistent ridge-forming yellowish sandstones, 5'ellowish 

 sandy shales, and coal beds. 



The Lance formation of the Lance Creek area has yielded abundant fossil 

 remains of vertebrates, invertebrates, and plants. The dinosaur remains, most of 

 which were collected from the area included in figure 2, have been discussed recently 

 by Russell ' and Lull.- The mammaUan fauna has been thoroughly treated by 

 Simpson,^ and the invertebrates have been listed by both Stanton * and Henderson.^ 

 Up to the present report the plant remains have not been systematically treated, and 

 only a provisional list of species has been published by Knowlton.'^ 



Except for the few specimens kindly loaned to me by the U. S. National Mu- 

 seum, the plant remains described in the present report were collected by me from 

 the Lance formation at the foUowing localities, shown in figure 2: 



Locality P3853. Base of low ridge, near center of SE. \ sec. 23, T. 36 N., R. 65 W. (See 

 plate 1, figs. 1, 2.) Leaves occur in great numbers in a dull-graj^ hard, calcareous sandstone, 

 which is a lenticular unit within a thicker unit of gray, carbonaceous, sandy shales and thin lignite 

 beds. The horizon is about 210 feet above the top of the Fox Hills sandstone. The following 

 species of plants were obtained here: 



Anona? robusta Asplenites tenellum 



Araucarites longifolia Canna? magnifolia 



' Russell, L., Proc. .\racr. Philos. Soc. vol. 69, 139-141, 1930. 



> Lull, R. S., Mcm. Peabody Mus. Nat. Hist., vol. 3, pt. 3, 8, 15, 1933. 



'Simpaon, G. G.. Mem. Peabody Mus. Nat. Hist., vol. 3, pt. 1, 97-139, 146, 149, 150, 1929. 



«Stanton, T. W., and Knowlton, F. H., op. cit., 128-1.36, 1897. 



• Henderson, J., Gcol. Soc. Amer., Spcc. Paper No. 3, 33, 1935. 



« Knowlton, F. H., Proc. Washington .Vcad. Sci., vol. 11, 180, 1909. 



